Infusion pump systems and methods

ABSTRACT

Some embodiments of an infusion pump system can include a controller in electrical communication with a pump device so as to provide selected dosages of a medicine to a user over a period of time. The infusion pump system can employ a number of power management techniques to reduce the likelihood current drain of a rechargeable battery of the infusion pump system.

CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No.13/023,820 filed on Feb. 9, 2011 (now U.S. Pat. No. 8,852,152), theentire contents of which are hereby incorporated by reference

TECHNICAL FIELD

This document relates to a portable infusion pump system, such as awearable insulin pump system that delivers insulin to a user.

BACKGROUND

Pump devices are commonly used to deliver one or more fluids to atargeted individual. For example, a medical infusion pump device may beused to deliver a medicine to a patient as part of a medical treatment.The medicine that is delivered by the infusion pump device can depend onthe condition of the patient and the desired treatment plan. Forexample, infusion pump devices have been used to deliver insulin to thevasculature of diabetes patients so as to regulate blood-glucose levels.

In some circumstances, the infusion pump devices may operate on batterypower to facilitate portability of the pump devices. In someapplications, it can be cost effective over the life of the infusionpump to utilize a rechargeable battery rather than a single use battery,as the rechargeable battery may be recharged many times, which canoffset the higher initial cost of the rechargeable battery as comparedto a single-use battery. Even during periods when the infusion pumpdevice is not being used, circuitry of the device may drain current fromthe rechargeable battery. To reduce likelihood of an over-dischargecondition of the rechargeable battery, which may damage the rechargeablebattery and adversely affect its life cycle capacity, it is desirable tominimize idle current of the rechargeable battery during periods ofnon-use.

SUMMARY

Some embodiments of an infusion pump system can include a controller inelectrical communication with a pump device so as to provide selecteddosages of a medicine to a user over a period of time. The infusion pumpsystem can employ a number of power management techniques to reduce thelikelihood current drain of a rechargeable battery of the infusion pumpsystem. Thus, the infusion pump system can preserve the energy supply ofthe rechargeable battery in an efficient manner to reduce the likelihoodof over-discharge of the rechargeable battery, for example, duringperiods when the system is idle or stored prior to use (e.g., shelflife). In some circumstances, the infusion pump system can be configuredin a manner that prolongs the useful life of the rechargeable battery.

In particular embodiments, a portable infusion pump system may include apump device and a controller device that is electrically connectable tothe pump device. The pump device may include a pump housing that definesa space to receive a medicine, and a drive system to dispense themedicine from the pump device when the medicine is received in the spaceof the pump housing. The controller device may electrically connect tothe pump device so as to control dispensation of the medicine from thepump device. The controller device may include a battery pack includinga voltage output terminal, a return terminal, a third terminal, and atleast one rechargeable battery cell that is coupled to the voltageoutput terminal. The rechargeable battery cell may provide electricalenergy to at least one of a component of the controller device and thedrive system of the pump device. The controller device may furtherinclude a monitor circuit that senses a voltage of the at least onerechargeable battery cell, a first resistor coupled between the at leastone rechargeable battery cell and a voltage sense terminal of themonitor circuit, and a second resistor coupled between the voltage senseterminal of the monitor circuit and the third terminal of the batterypack. When a low-resistance connection is provided between the thirdterminal of the battery pack and the return terminal of the batterypack, the monitor circuit can shift the battery pack to a low power modethat reduces electrical current drawn from the at least one rechargeablebattery cell.

In other embodiments, a method of controlling a portable infusion pumpsystem may include providing a controller device that is electricallyconnectable to a pump device so as to control dispensation of medicinefrom the pump device. The controller device may include a battery packincluding a voltage output terminal, a return terminal, a thirdterminal, and at least one rechargeable battery cell that is coupled tothe voltage output terminal. The rechargeable battery cell can beconfigured to provide electrical energy to at least one of a userinterface component of the controller device and a drive system of thepump device. The controller device may further include a monitor circuitthat senses a voltage of the at least one rechargeable battery cell, afirst resistor coupled between the at least one rechargeable batterycell and a voltage sense terminal of the monitor circuit, and a secondresistor coupled between the voltage sense terminal of the monitorcircuit and the third terminal of the battery pack. The method may alsoinclude providing a low-resistance connection between the third terminalof the battery pack and the return terminal of the battery pack to causethe safety integrated circuit to put the battery pack in a low powermode that reduces electrical current drawn from the at least onerechargeable battery cell.

Some or all of the embodiments described herein may provide one or moreof the following advantages. First, some embodiments of the infusionpump system may include a configuration minimizes an idle current drainof a rechargeable battery. This may preserve the energy supply of therechargeable battery in an efficient manner to prevent over-discharge ofthe rechargeable battery and prolong the useful life of the rechargeablebattery.

Second, certain embodiments of an infusion pump system may include aconfiguration that can place the rechargeable battery into a low powermode even when the rechargeable battery retains a substantially fullcharge level, which is greater than a predefined low voltage thresholdvalue established by a battery monitoring circuit device. This maypreserve the energy supply of the rechargeable battery in an efficientmanner to prevent over-discharge of the rechargeable battery and prolongthe useful life of the rechargeable battery.

Third, some embodiments of the infusion pump system can cause therechargeable battery to enter a low power mode without an application ofan external voltage source. This may provide convenience because the lowpower mode may be entered without having to connect a separate device orpower source, thereby simplifying the manufacturing and storage processfor the controller device.

Fourth, using techniques discussed herein, some embodiments can permitthe rechargeable battery to be placed in the low power mode followingmanufacture of the rechargeable battery, or alternatively duringassembly and production of the infusion pump system. This may preservethe energy supply of the rechargeable battery in an efficient manner toprevent over-discharge of the rechargeable battery, and may permit therechargeable battery to retain charge so that the system is usableimmediately upon unpacking after shipping and storage (e.g., a period ofshelf life) of the system.

Fifth, some embodiments of the infusion pump system can cause therechargeable battery to enter a low power mode following auser-initiated action, such as disconnecting the pump assembly from thecontroller device. This may preserve the energy supply of therechargeable battery in an efficient manner to prevent over-discharge ofthe rechargeable battery and prolong the useful life of the rechargeablebattery.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of an infusion pump system in accordancewith some embodiments.

FIG. 2 is a perspective view of the infusion pump system of FIG. 1 in adetached state.

FIG. 3 is a perspective view of an infusion pump system, in accordancewith some embodiments.

FIGS. 4-5 are perspective views of the pump device of FIGS. 1-2 beingdiscarded and the controller device of FIGS. 1-2 being reused with a newpump device.

FIG. 6 is an exploded perspective view of a controller device for aninfusion pump system, in accordance with some embodiments.

FIGS. 7A and 7B are exploded perspective views of a portion of thecontroller device of FIG. 6.

FIG. 8 is an exploded perspective view of a pump device for an infusionpump system, in accordance with some embodiments.

FIG. 9 is a schematic diagram of a battery pack device for an infusionpump controller, in accordance with some embodiments.

FIG. 10 is another schematic diagram of a battery pack device for aninfusion pump controller, in accordance with some embodiments.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Referring to FIG. 1, an infusion pump system 10 can include a pumpdevice 100 and a controller device 200 that communicates with the pumpdevice 100. The pump device 100 in this embodiment includes a housingstructure 110 that defines a cavity 116 in which a fluid cartridge 120can be received. The pump device 100 also can include a cap device 130to retain the fluid cartridge 120 in the cavity 116 of the housingstructure 110. The pump device 100 can include a drive system (describedin more detail below) that advances a plunger 125 in the fluid cartridge120 so as to dispense fluid therefrom. The controller device 200communicates with the pump device 100 to control the operation of thedrive system. When the controller device 200, the pump device 100(including the cap device 130), and the fluid cartridge 120 areassembled together, the user can (in some embodiments) conveniently wearthe infusion pump system 10 on the user's skin under clothing, in apouch clipped at the waist (e.g., similar to a cell phone pouch), or inthe user's pocket while receiving the fluid dispensed from the pumpdevice 100.

In some embodiments, the controller device 200 may be configured as areusable component that provides electronics and a user interface tocontrol the operation of the pump device 100. In such circumstances, thepump device 100 can be a disposable component that is disposed of aftera single use. For example, as described in more detail below inconnection with FIGS. 4-5, the pump device 100 can be a “one time use”component that is thrown away after the fluid cartridge 120 therein isexhausted. Thereafter, the user can removably attach a new pump device100′ (having a new medicine cartridge 120′) to the reusable controllerdevice 200 for the dispensation of fluid from a new fluid cartridge120′. Accordingly, the user is permitted to reuse the controller device200 (which may include complex or valuable electronics, as well as arechargeable battery) while disposing of the relatively low-cost pumpdevice 100 after each use. Such a pump system 10 can provide enhanceduser safety as a new pump device 100′ (and drive system therein) isemployed with each new fluid cartridge 120′.

The infusion pump system 10 may also include a rechargeable battery pack245 (also referred to herein as rechargeable battery 245; refer also toFIGS. 6-7) in the controller device 200 and a charger battery 345 (referalso to FIG. 8) in the pump device 100. The charger battery 345 can bedisposable in that it can be discarded with the pump device 100 afterexhaustion of the pump device 100. The rechargeable battery pack 245 canreceive electrical energy from the charger battery 345 to maintain abattery of the rechargeable battery pack 245 at a charge greater than athreshold charge level. As described in more detail below, therechargeable battery 245 can provide electrical energy to electronics ofthe controller device 200 and, in some circumstances, to the drivesystem 300 (FIG. 8) of the pump device 100 to dispense medicine to thepatient. For example, if the charger battery 345 housed in the pumpdevice becomes depleted, the rechargeable battery 245 housed in thecontroller device 200 can provide electrical power to the drive systemof the pump device to continue the medicine dispensation dosages.Accordingly, infusion pump system 10 can incorporate two batteries 245and 345 so that the rechargeable battery 245 housed in the controllerdevice 200 is recharged by the second battery 345 housed in the pumpdevice 100 when the controller device 200 is removably attached to thepump device 100. As described in more detail below, this feature alsopermits the rechargeable battery 245 to be stored (prior to use) in a“sleep” mode to conserve battery power and then switched to a normalmode by merely attaching the pump device 100 to the controller device200. In other embodiments, a monolithic infusion pump system can includea rechargeable energy source 245 and a replaceable battery 345, whichcan be individually removed from the infusion pump system.

As described in more detail below in connection with FIGS. 6-10, thecontroller device 200 can include circuitry to minimize current drain ofthe rechargeable battery 245. Because current drain of the rechargeablebattery reduces the amount of rechargeable battery energy available topower electronics of the infusion pump system 10, including electronicsof the controller device 200 and the pump assembly 100, minimizingcurrent drain of the rechargeable battery may be a priority. Forexample, it may be desirable to minimize current drain between the timethat the rechargeable battery 245 is manufactured and the time it isfirst used. It may similarly be desirable to minimize current drain ofthe rechargeable battery 245 when the pump assembly 100 (includingcharger battery 345) is disconnected from the controller device 200,especially if the controller device remains disconnected from a new pumpassembly and charger battery for an extended period of time, such as oneor more days. The techniques described herein may permit therechargeable battery 245 to be placed in a “low power” mode (such as a“sleep” or “storage” mode) even when the rechargeable battery 245 is atsubstantially full power level, which may minimize or otherwise reducean amount of current drawn from the rechargeable battery 245 and therebyconserve remaining electrical charge of the rechargeable battery 245.Additionally, the techniques described herein may permit therechargeable battery 245 to be placed in the low power mode withoutapplication of an external voltage source, and may be initiated based onan action of a user, or during a manufacturing or production step,according to various implementations.

Briefly, in use, the pump device 100 is configured to removably attachto the controller device 200 in a manner that provides a secure fitting,an overall compact size, and a reliable electrical connection that isresistant to water migration. For example, as described in more detailbelow in connection with FIGS. 1-5, the controller device 200 caninclude a housing 210 having a number of features that mate withcomplementary features of the pump housing 110. In such circumstances,the controller device 200 can removably attach with the pump device 100in a generally side-by-side configuration. The compact size permits theinfusion pump system 10 to be discrete and portable (as described belowin connection with FIG. 3). Moreover, at least one of the pump device100 or the controller device 200 can include a release member thatfacilitates an easy-to-use detachment and replacement process.

Referring again to FIG. 1, the pump system 10 can be a medical infusionpump system that is configured to controllably dispense a medicine fromthe cartridge 120. As such, the fluid cartridge 120 can contain amedicine 126 to be infused into the tissue or vasculature of a targetedindividual, such as a human or animal patient. For example, the pumpdevice 100 can be adapted to receive a medicine cartridge 120 in theform of a carpule that is preloaded with insulin or another medicine foruse in the treatment of Diabetes (e.g., Byetta®, Symlin®, or others).Such a cartridge 120 may be supplied, for example, by Eli Lilly and Co.of Indianapolis, Ind. Other examples of medicines that can be containedin the fluid cartridge 120 include: pain relief drugs, hormone therapy,blood pressure treatments, anti-emetics, osteoporosis treatments, orother injectable medicines. The fluid cartridge 120 may have otherconfigurations. For example, the fluid cartridge 120 may comprise areservoir that is integral with the pump housing structure 110 (e.g.,the fluid cartridge 120 can be defined by one or more walls of the pumphousing structure 110 that surround a plunger to define a reservoir inwhich the medicine is injected or otherwise received).

In some embodiments, the pump device 100 can include one or morestructures that interfere with the removal of the medicine cartridge 120after the medicine cartridge 120 is inserted into the cavity 116. Forexample, the pump housing structure 110 can include one or more retainerwings that at least partially extend into the cavity 116 to engage aportion of the medicine cartridge 120 when the medicine cartridge 120 isinstalled therein. Such a configuration may facilitate the“one-time-use” feature of the pump device 100. In some embodiments, theretainer wings can interfere with attempts to remove the medicinecartridge 120 from the pump device 100, thus ensuring that the pumpdevice 100 will be discarded along with the medicine cartridge 120 afterthe medicine cartridge 120 is emptied, expired, or otherwise exhausted.Accordingly, the pump device 100 can operate in a tamper-resistant andsafe manner because the pump device 100 can be designed with apredetermined life expectancy (e.g., the “one-time-use” feature in whichthe pump device is discarded after the medicine cartridge 120 isemptied, expired, or otherwise exhausted).

Still referring to FIG. 1, the controller device 200 can be removablyattached to the pump device 100 so that the two components aremechanically mounted to one another in a fixed relationship. Such amechanical mounting can form an electrical connection between theremovable controller device 200 and the pump device 100. For example,the controller device 200 can be in electrical communication with aportion of a drive system (not shown in FIG. 1) of the pump device 100.As described in more detail below, the pump device 100 can include adrive system that causes controlled dispensation of the medicine orother fluid from the cartridge 120. In some embodiments, the drivesystem incrementally advances a piston rod (not shown in FIG. 1)longitudinally into the cartridge 120 so that the fluid is forced out ofan output end 122. A septum 121 (FIG. 1) at the output end 122 of thefluid cartridge 120 can be pierced to permit fluid outflow when the capdevice 130 is connected to the pump housing structure 110. For example,the cap device may include a penetration needle that punctures theseptum 121 during attachment of the cap device 130 to the housingstructure 110. Thus, when the pump device 100 and the controller device200 are attached and thereby electrically connected, the controllerdevice 200 communicates electronic control signals via ahardwire-connection (e.g., electrical contacts or the like) to the drivesystem or other components of the pump device 100. In response to theelectrical control signals from the controller device 200, the drivesystem of the pump device 100 causes medicine to incrementally dispensefrom the medicine cartridge 120. Power signals, such as signals from therechargeable battery 245 of the controller device 200 and from thecharger battery 345 of the pump device 100 may also be passed betweenthe controller device 200 and the pump device 100.

As shown in FIG. 1, the pump device 100 can include an electricalconnector 118 (e.g., having conductive pads, pins, and the like) that isexposed to the controller device 200 and that mates with a complementaryelectrical connector (refer to connector 218 in FIG. 2) on the adjacentface of the controller device 200. The electrical connectors 118 and 218provide the electrical communication between the control circuitry(refer, for example, to FIGS. 6, 7A and 7B) housed in the controllerdevice 200 and at least a portion of the drive system or othercomponents of the pump device 100. For example, in some embodiments, theelectrical connectors 118 and 218 can permit the transmission ofelectrical control signals to the pump device 100 and the reception offeedback signals (e.g., sensor signals) from particular componentswithin the pump device 100. The electrical connectors 118 and 218 maysimilarly facilitate transmission of one or more power signals from therechargeable battery pack 245 to the pump device 100, where the signalsmay be used to provide power to components of the pump device 100, or totransmit one or more power signals from the charger battery 345 to thecontroller device, where the signals may be used to charge therechargeable battery 245 or to power components of the controller device200.

Still referring to FIG. 1, the controller device 200 can include a userinterface 220 that permits a user to monitor the operation of the pumpdevice 100. In some embodiments, the user interface 220 can include adisplay device 222 and one or more user-selectable buttons (e.g.,several buttons 224 are shown in the embodiment of FIG. 1). The displaydevice 222 can include an active area in which numerals, text, symbols,images, or a combination thereof can be displayed. For example, thedisplay device 222 can be used to communicate a number of settings ormenu options for the infusion pump system 10. In this embodiment, theuser may press one or more of the buttons to shuffle through a number ofmenus or program screens that show particular settings and data (e.g.,review data that shows the medicine dispensing rate, the total amount ofmedicine dispensed in a given time period, the amount of medicinescheduled to be dispensed at a particular time or date, the approximateamount of medicine remaining in the cartridge 120, or the like). In someembodiments, the user can adjust the settings or otherwise program thecontroller device 200 by pressing one or more buttons of the userinterface 220. For example, in embodiments of the infusion pump system10 configured to dispense insulin, the user may press one or more of thebuttons to change the dispensation rate of insulin or to request that abolus of insulin be dispensed immediately or at a scheduled, later time.In some implementations, the display device 222 may also be used tocommunicate information regarding remaining battery life.

Accordingly, when the controller device 200 is connected to the pumpdevice 100, the user can be provided with the opportunity to readilymonitor the infusion pump operation by simply viewing the user interface220 of the controller device 200 connected to the pump device 100. Suchmonitoring capabilities may provide comfort to a user who may haveurgent questions about the current operation of the pump device 100.Also, in these embodiments, there may be no need for the user to carryand operate a separate module to monitor the operation of the infusionpump device 100, thereby simplifying the monitoring process and reducingthe number of devices that must be carried by the user. If a need arisesin which the user desires to monitor the operation of the pump device100 or to adjust the settings of the pump system 10 (e.g., to request abolus amount of medicine), the user can readily operate the userinterface 220 of the controller device 200, which is removably attachedto the pump device 100, without the requirement of locating andoperating a separate monitoring module.

Referring now to FIG. 2, when the infusion pump system 10 operates, thecontroller device 200 can be removably attached to the pump device 100in a side-by-side arrangement. For example, the pump device 100 may bemoved in a longitudinal direction (e.g., refer to direction 219 in FIG.4) toward the controller device 200 until the complementary featuresconnect and secure the separate components in the side-by-sidearrangement. In these circumstances, the pump device 100 and thecontroller device 200 can be separate components that fit together, butthe overall size of the combined assembly can be reduced because thereis no requirement for one component (e.g., the controller device or pumpdevice) to surround or envelop the second component (e.g., the pumpdevice or controller device). Moreover, in some embodiments, the pumpdevice 100 and controller device 200 can be readily attached togetherwith a “one-movement” process that is convenient to the user.

The controller device 200 can include a controller housing structure 210having a number of features that are configured to mate withcomplementary features of the pump housing structure 110 so as to form areleasable mechanical connection. For example, the pump housingstructure 110 can include a barrel 111 that mates with a complementarybarrel channel 211 of the controller housing 210. In variousimplementations, the pump device 100 and the controller device 200 canbe mounted to one another so that the assembled system 10 is resistantto water migration both into the pump housing structure 110 and thecontroller housing structure 210. Such a configuration can also providewater-resistant protection for the electrical connection between thepump device 100 and the controller device 200. Thus, the sensitiveinternal components in the controller device 200 and the pump device 100can be reliably protected from water migration if the user encounterswater (e.g., rain, incidental splashing, and the like) while using thepump system 10.

Referring to FIG. 3, the infusion pump system 10 can be configured to beportable and can be wearable and concealable. For example, a user canconveniently wear the infusion pump system 10 on the user's skin (e.g.,skin adhesive) underneath the user's clothing or carry the pump device100 in the user's pocket (or other portable location) while receivingthe medicine dispensed from the pump device 100. The pump system 10 isshown in FIG. 3 as being held in a user's hand 5 so as to illustrate anexemplary size of the system 10 in accordance with some embodiments.This embodiment of the infusion pump system 10 is compact so that theuser can wear the portable infusion pump system 10 (e.g., in the user'spocket, connected to a belt clip, adhered to the user's skin, or thelike) without the need for carrying and operating a separate module. Insuch embodiments, the cap device 130 of the pump device 100 can beconfigured to mate with an infusion set 146. In general, the infusionset 146 can be a tubing system that connects the infusion pump system 10to the tissue or vasculature of the user (e.g., to deliver medicine intothe tissue or vasculature under the user's skin). The infusion set 146can include a flexible tube 147 that extends from the pump device 100 toa subcutaneous cannula 149 that may be retained by a skin adhesive patch(not shown) that secures the subcutaneous cannula 149 to the infusionsite. The skin adhesive patch can retain the infusion cannula 149 influid communication with the tissue or vasculature of the patient sothat the medicine dispensed through the tube 147 passes through thecannula 149 and into the user's body. The cap device 130 can providefluid communication between the output end 122 (FIG. 1) of the medicinecartridge 120 and the tube 147 of the infusion set 146.

In some embodiments, the infusion pump system 10 can be pocket-sized sothat the pump device 100 and controller device 200 can be worn in theuser's pocket or in another portion of the user's clothing. In somecircumstances, the user may desire to wear the pump system 10 in a morediscrete manner. Accordingly, the user can pass the tube 147 from thepocket, under the user's clothing, and to the infusion site where theadhesive patch can be positioned. As such, the pump system 10 can beused to deliver medicine to the tissues or vasculature of the user in aportable, concealable, and discrete manner.

In some embodiments, the infusion pump system 10 can be configured toadhere to the user's skin directly at the location in which the skin ispenetrated for medicine infusion. For example, a rear surface 102 (FIG.2) of the pump device 100 can include a skin adhesive patch so that thepump device 100 can be physically adhered to the skin of the user at aparticular location. In these embodiments, the cap device 130 can have aconfiguration in which medicine passes directly from the cap device 130into an infusion cannula 149 that is penetrated into the user's skin. Insome examples, the user can temporarily detach the controller device 200(while the pump device 100 remains adhered to the skin) so as to viewand interact with the user interface 220.

Referring now to FIGS. 4-5, the infusion pump system 10 can be operatedsuch that the pump device 100 is a disposable, non-reusable componentwhile the controller device 200 is a reusable component. In thesecircumstances, the pump device 100 may be configured as a “one-time-use”device that is discarded after the medicine cartridge is emptied,expired, or otherwise exhausted. Thus, in some embodiments, the pumpdevice 100 can be designed to have an expected operational life of about1 day to about 30 days, about 1 day to about 20 days, about 1 to about14 days, or about 1 day to about 7 days—depending on the volume ofmedicine in the cartridge 120, the dispensation patterns that areselected for the individual user, and other factors. For example, amedicine cartridge 120 containing insulin can have an expected usagelife of about 7 days after the cartridge is removed from a refrigeratedstate and the septum 121 is punctured. In some circumstances, thedispensation pattern selected by the user can cause the insulin to beemptied from the medicine cartridge 120 before the 7-day period. If theinsulin is not emptied from the medicine cartridge 120 after the 7-dayperiod, the remaining insulin can become expired sometime thereafter. Ineither case, the pump device 100 and the medicine cartridge 120 thereincan be discarded after exhaustion of the medicine cartridge 120 (e.g.,after being emptied, expired, or otherwise not available for use).

The controller device 200, however, may be reused with subsequent newpump devices 100′ and new medicine cartridges 120′. As such, the controlcircuitry, the user interface components, the rechargeable battery pack245, and other components that may have relatively higher manufacturingcosts can be reused over a longer period of time. For example, in someembodiments, the controller device 200 can be designed to have anexpected operational life of about 1 year to about 7 years, about 2years to about 6 years, or about 3 years to about 5 years—depending on anumber of factors including the usage conditions for the individualuser. Accordingly, the user can be permitted to reuse the controllerdevice 200 (which can include complex or valuable electronics, and arechargeable battery pack) while disposing of the relatively low-costpump device 100 after each use. Such a pump system 10 can provideenhanced user safety as a new pump device 100′ (and drive systemtherein) is employed with each new fluid cartridge 120′.

Referring to FIGS. 4-5, the same controller device 200 can be reusedwith a new pump device 100′ having a new medicine cartridge 120′retained therein, and the previously used pump device 100, including theexhausted medicine cartridge, can be discarded in a discard bin 20. Thenew pump device 100′ (FIG. 4) can have a similar appearance, formfactor, and operation as the previously used pump device 100, and thusthe new pump device 100′ can be readily attached to the controllerdevice 200 for controlled dispensation of medicine from the new medicinecartridge 120′. In some embodiments, the user can prepare the new pumpdevice 100′ for use with the controller device 200. For example, theuser may insert the new medicine cartridge 120′ in the cavity 116 of thenew pump device 100′ and then join the cap device 130 to the pumphousing to retain the new medicine cartridge 120′ therein (refer, forexample, to FIG. 1). Although the tubing 147 of the infusion set 146 isnot shown in FIG. 4, it should be understood that the tubing 147 can beattached to the cap device 130 prior to the cap device 130 being joinedwith the housing 110. For example, a new infusion set 146 can beconnected to the cap device 130 so that the tubing 147 can be primed(e.g., a selected function of the pump device 100 controlled by thecontroller device 200) before attaching the infusion set patch to theuser's skin. As shown in FIG. 4, the new medicine cartridge 120′ may befilled with medicine such that the plunger 125 is not viewable throughthe barrel 111.

The new pump device 100′ can be removably attached to the controllerdevice 200 to assemble into the infusion pump system 10 for delivery ofmedicine to the user. As previously described, the guided motion in thelongitudinal direction 219 provides the user with a convenient“one-movement” process to attach the pump device 100′ and the controllerdevice 200. For example, the user can readily slide the pump device 100′and the controller device 200 toward one another in a single movement(e.g., in the longitudinal direction 219) that causes both a physicalconnection and an electrical connection. Thus, the infusion pump system10 can permit users to readily join the pump device 100′ and thecontroller device 200 without compound or otherwise difficult handmovements—a feature that can be beneficial to child users or to elderlyusers.

Referring now to FIG. 6, the controller device 200 (shown in an explodedview) houses a number of components that can be reused with a series ofsuccessive pump devices 100. In particular, the controller device 200can include controller circuitry 240 and rechargeable battery pack 245,each arranged in the controller housing 210. As described above,rechargeable battery pack 245 may provide electrical energy tocomponents of controller circuitry 240, other components of thecontroller device (e.g., a display device 222 and other user interfacecomponents, sensors, or the like), or components of the pump device 100.Controller circuitry 240 may be configured to communicate control orpower signals to the drive system of the pump device 100, or to receivepower or feedback signals from the pump device 100.

In some embodiments, the controller circuitry 240 can include a logicboard 520 in communication with a power board 540. In general, the logicboard 520 (and also the power board 540) may include components that areused to control operation of the infusion pump system 10, and the powerboard 540 may include components that receive battery power signals fromthe rechargeable battery 245, the charger battery 345, or both, andprovide sources of power for the electrical components of the controllerdevice 200 and the pump device 100. It should be understood thatalthough the logic board 520 are power board 540 are depicted as aprinted circuit boards, one or both can have other forms, includingmultiple boards, a flexible circuit substrate, and other configurations.In some implementations, the logic board 520 and power board 540 may becombined as a single printed circuit board.

Still referring to FIG. 6, the user interface 220 of the controllerdevice 200 can include input components and/or output components thatare electrically connected to the controller circuitry 240. For example,the user interface 220 can include the display device 222 having anactive area that outputs information to a user and buttons 224 that theuser can use to provide input. Here, the display device 222 can be usedto communicate a number of settings or menu options for the infusionpump system 10. In some embodiments, the controller circuitry 240 canreceive input commands from a user's button selections and thereby causethe display device 222 to output a number of menus or program screensthat show particular settings and data (e.g., review data that shows themedicine dispensing rate, the total amount of medicine dispensed in agiven time period, the amount of medicine scheduled to be dispensed at aparticular time or date, the approximate amount of medicine remainingthe cartridge 120, the amount of battery life remaining, or the like).As previously described, the controller circuitry 240 can beprogrammable to cause the controller circuitry 240 to change any one ofa number of settings for the infusion pump system 10. For example, theuser may provide one or more instructions to adjust a number of settingsfor the operation of the infusion pump system 10. Such settings may bestored in the memory devices arranged in the controller circuitry 240.The controller circuitry 240 can include other components, such assensors, that are electrically connected to the logic board 520.

Some embodiments of the controller circuitry 240 can include a cableconnector (e.g., a USB connection port or another data cable port) thatis accessible on an external portion of the controller housing 210. Assuch, a cable can be connected to the controller circuitry 240 to uploaddata or program settings to the controller circuitry 240 or to downloaddata from the controller circuitry 240. For example, historical data ofmedicine delivery can be downloaded from the controller circuitry 240(via the cable connector) to a computer system of a physician or a userfor purposes of analysis and program adjustments. Optionally, the datacable can also provide recharging power.

Referring now to FIG. 7A, a perspective view of portions of controllercircuitry 240 and the rechargeable battery pack 245 is shown.Rechargeable battery pack 245 may include one or more lithium-ion orlithium-polymer battery cells 500, and may include a battery safetycircuit 502 (described in more detail below in connection FIGS. 9-10).The rechargeable battery pack 245 includes three terminals 504, 506, and508 according to some embodiments, as represented by wires 504, 506, and508, which individually couple the terminals of the battery pack 245 toa connector 510. As will be described below with reference to FIGS.9-10, the terminals may include a voltage output terminal 504 and areturn terminal 506, as well as a third terminal 508 that can be used toplace the rechargeable battery pack 245 into a low power mode (even whenthe it is substantially fully charged). Controller circuitry 240includes logic board 520 and power board 540, and may include one ormore pairs of mating connectors (not shown) that may permit signals tobe coupled between the logic board 520 and the power board 540.

The rechargeable battery pack 245 can be coupled to the power board 540.For example, the connector 510 may be connected with a mating connector542 disposed on the power board 540, and may thereby couple the threeterminals 504, 506, 508 from the battery pack 245 to the power board 540and further to one or more components for controller circuitry 240.

The rechargeable battery pack 245 can include a lithium-ion orlithium-polymer battery 500. In some implementations, the lithium-ion orlithium-polymer battery 500 may be a 3.8 volt battery. The rechargeablebattery pack 245 can include a high-current-output battery that iscapable of discharging a brief current burst to power, for example, thedrive system 300 of the pump device 100, and can also provide energysources for various electronic components of the infusion pump system10. In other embodiments, it should be understood that the rechargeablebattery 245 can include a capacitor device capable of being rechargedover time and intermittently discharging a current burst to activate thedrive system 300. Additional embodiments of the rechargeable battery 245can include a combination of batteries and capacitors.

In some embodiments, one or more power supply components (e.g., disposedon power board 540) may receive charge energy from the rechargeablebattery pack 245 and convert the energy into one or more usable powersources at one or more voltage levels for electronic components of theinfusion pump system. The electronic components may reside, for example,in the pump assembly 100 or in the controller device 200.

The rechargeable battery 245 may be capable of accepting and storingelectrical energy over time (e.g., “trickle charge”). For example, therechargeable battery 245 can be charged with energy supplied from thecharger battery 345, according to some implementations. The hard-wiredtransmission of electrical energy from the rechargeable battery 245 tothe drive system 300 can occur through the previously describedconnectors 118 and 218 (FIGS. 1-2). The rechargeable battery 245 canreceive electrical energy from a power source housed in the pump device100 (e.g., the charger battery 345), from a plug-in wall charger, from acable connector (e.g., a USB connection port that is connected to thecontroller circuitry 240), or from another charging device (e.g., acharging cradle), according to some implementations.

Accordingly, the infusion pump system 10 can include two power sources345 and 245—one arranged in the disposable pump device 100 and anotherarranged in the reusable controller device 200—which can permit a userto continually operate the controller device 200 without having torecharge a battery via a plug-in wall charger or other cable. Becausethe controller device 200 can be reusable with a number of pump devices100 (e.g., attach the new pump device 100′ after the previous pumpdevice 100 is expended and disposed), the rechargeable battery 245 inthe controller device can be recharged over a period of time, each timewhen a new pump device 100′ is connected thereto. Such a configurationcan be advantageous in those embodiments where the pump device 100 isconfigured to be a disposable, one-time-use device that attaches to areusable controller device 200. For example, in those embodiments, the“disposable” pump devices 100 recharges the rechargeable battery 245 inthe “reusable” controller device 200, thereby reducing or possiblyeliminating the need for separate recharging of the controller device200 via a power cord plugged into a wall outlet.

Referring again to FIG. 7A, a main processor 522 is shown residing onlogic board 520. In various implementations, processor 522 may compriseone or more microprocessors, microcontrollers, digital signalprocessors, instantiated cores within one or more programmable logicdevices (e.g., application specific integrated circuit, fieldprogrammable gate array, complex programmable logic device), or thelike. Processor 522 may execute instructions and perform tasksassociated with the infusion pump system. For example, the processor 522may coordinate the electrical communication to and/or from thecontroller device 200 (e.g., communication between the controller device200 and the pump device 100). Processor 522 may receive inputsindicative of various statuses relating to the infusion pump system. Forexample, the processor 522 may receive one or more inputs that indicatea charge status of the rechargeable battery 245, a charge status of thecharger battery 345, or both. As will be described in more detail below,the processor 522 may control a switch (e.g., switch 562 or switch 564,see FIGS. 9-10) that may cause the rechargeable battery pack 245 toenter a low power mode.

In various implementations, processor 522 executes instructions storedin memory locations internal of the processor 522 or in memory locationsin one or more memory devices external of the processor 522. Forexample, in some embodiments the processor 522 may include on-boardrandom access memory (RAM), where instructions may be loaded andexecuted therefrom by the processor 522. Processor 522 may also includevarious forms of on-board non-volatile memory for storing instructionsor data in some implementations, including but not limited to EPROM,EEPROM, Flash, and the like. In some embodiments, memory devicesexternal of the processor 522 are used. A memory device 526 may storeinstructions, data, or both, for use by the processor 522. In someimplementations, memory device 526 includes FRAM data storage. Memorydevice 526 may store user settings and alarms, as well as parameters forthe infusion pump system 10, including last-used pump parameters. Aswill be described below with reference to FIGS. 9-10, the processor 522may provide an output that causes the rechargeable battery pack 245 toenter a low power mode.

Referring now to FIG. 7B, the controller circuitry 240 can includecharger control circuitry, which can be disposed on the power board 540.The charger control circuitry can serve as a gatekeeper to operate thecharging and discharging of the rechargeable battery 245. In someimplementations, the charger control circuitry can cause therechargeable battery 245 to output power to the electronics and displayof the controller device 200, to output power to the drive system 300housed in the pump device 100, to output power to one or more othercomponents of the infusion pump system 10, to receive recharging powerfrom the charger battery 345, or some combination of the foregoing. Insome embodiments, the charger control circuitry can be activated so asto provide the recharging power to the rechargeable battery 245 from thecharger battery 345. Optionally, a DC-DC converter can be used to boostthe voltage input (e.g., 1.5V in some embodiments) from the chargerbattery 345 to a higher, charging output voltage, which may be used tocharge the rechargeable battery 245. In some embodiments, the chargingoutput voltage may be about 3.8 volts. In some embodiments, a seriesresistor may be used to limit a maximum battery charge current. Also, insome implementations, the charger control circuitry may cause therechargeable battery 245 to be recharged when the pump body 100 isattached to the controller device 200.

Referring now to FIG. 8, in some embodiments, the pump device 100 caninclude a power source 345, referred to above as a charger battery. Insome embodiments, the power source 345 is an alkaline battery cell, suchas a 1.5 Volt “AAA” alkaline battery cell. The power source 345 may becapable of transmitting electrical energy to the controller device 200when the pump device 100 is attached to the controller device 200, viaconnectors 118 and 218 as described above. For example, the power source345 may be used to charge the rechargeable battery pack 245 when thepump device 100 is attached to the controller device 200. In someembodiments, the power source 345 is used to provide energy to the drivesystem 300 of the pump device 100, and also to electronic components ofthe controller device 200. In some circumstances, the power source 345,which may be a “AAA” battery, may provide the energy to power allaspects of the infusion pump system 10. In some circumstances, therechargeable battery 245 may provide the energy to power all aspects ofthe infusion pump system 10. In some circumstances, the rechargeablebattery 245 and the power source 345 (charger battery) may each beresponsible for powering particular aspects of the infusion pump system10. In some circumstances, the rechargeable battery 245 may provide theenergy to supplement the energy provided by the power source 345 topower aspects of the infusion pump system.

Referring again to FIG. 8, the pump device 100 can include the drivesystem 300 that is controlled by the controller device 200. The drivesystem 300 can accurately and incrementally dispense fluid from the pumpdevice 100 in a controlled manner. The pump device 100 can include aconnector circuit to facilitate the transfer of signals to and from theelectrical connector 118. In some implementations, the connector circuitin the pump device 100 can include a memory device that can store dataregarding the pump device 100 and its operational history. As previouslydescribed, the electrical connector 118 of the pump device 100 can matewith the connector 218 (FIG. 2) of the controller device 200 so thatelectrical communication can occur between the pump device 100 and thecontroller device 200. In some embodiments, the connector circuit canoperate as a passageway for the control signals (from the controllercircuitry 240 of the controller device 200) to transmit to the drivesystem 300. The connector circuit can also operate as a passageway forthe electrical power from the charger battery 345 to pass to thecontroller device 200 for recharging of the rechargeable battery 245.Furthermore, the connector circuit can operate as a passageway forfeedback signals from the drive system 300 to the controller circuitry240 of the controller device 200.

Referring now to FIG. 9, a schematic diagram of a battery pack deviceand circuit for an infusion pump controller is shown. The battery packdevice may correspond to the rechargeable battery 245, according to someimplementations. Using the techniques described herein, the battery packdevice 245 may be placed into a low power mode, which may preserve aremaining charge of the battery pack and minimize idle current drainfrom the battery pack. A battery 500, such as the one or morerechargeable battery cells of battery pack 245, is coupled via a firstresistor 550 to a voltage sense terminal 553 of a battery protectionintegrated circuit (“IC”) 501. Additionally, the positive batteryterminal is coupled to a voltage output terminal 504 of the battery pack245. A capacitor 552 is coupled between the voltage sense terminal 553and a ground reference 575 of the battery 500, to which a returnterminal 551 of the battery protection IC 501 is also connected. Thefirst resistor 550 and the capacitor 552 form a high-pass filter circuitto prevent battery voltage spikes from reaching the voltage inputterminal 553 of the battery protection IC 501.

In some implementations, battery protection IC 501 may be a SeikoS-8211C device, although other battery protection devices mayalternatively be used. In the embodiment shown in FIG. 9, threeadditional pins of the battery protection IC 501 are shown. Output pins“DO” 557 and “CO” 559 are coupled to switches 556 and 558, respectively,so that battery protection IC 501 may independently control the switches556 and 558. One terminal of switch 556 is coupled to terminal of switch558, while a second terminal of switch 556 is coupled to the groundreference 575 of the battery 500. A voltage monitoring terminal 561 ofthe battery protection IC 501 is coupled to a current limiting resistor560, where the other terminal of the current limiting resistor 560 isconnected to the second terminal of switch 558 and to a return terminal506 of the battery pack 245. Switches 556 and 558 are depicted asMOSFETs, but other types of switches (e.g., bipolar junction transistorsor the like) could alternatively be used.

Under normal operating conditions, the battery protection IC 501controls switches 556 and 558 to be closed, so that a conductive path isformed (through switches 556, 558) between the ground reference 575 ofbattery 500 and the return terminal 506 of the battery pack 245. Also,under normal operating conditions the battery protection IC 501 monitorsthe voltage across its voltage sense terminal 553 and its returnterminal 551, where this voltage is typically the voltage of battery500. If the battery protection IC 501 detects that the voltage acrossits voltage sense terminal 553 and its return terminal 551 falls below apredetermined low voltage threshold value for a predetermined period oftime, the battery protection IC 501 perceives an under-voltage conditionand controls switch 556 to open, thereby breaking the conductive pathbetween the ground reference 575 of the battery 500 and the returnterminal 506 of the battery pack 245. In some embodiments, the lowvoltage threshold value may be about 2.8 volts. By contrast, if thebattery protection IC 501 detects that the voltage across its voltagesense terminal 553 and its return terminal 551 is above a predeterminedhigh voltage threshold value for a predetermined period of time, thebattery protection IC 501 perceives an over-voltage condition andcontrols switch 558 to open, thereby also breaking the conductive pathbetween the ground reference 575 of the battery 500 and the returnterminal 506 of the battery pack 245.

In the case of a detected under-voltage condition, the batteryprotection IC 501 places the battery pack 245 in a low power mode. Inthe low power mode, the battery protection IC 501 may cease to monitorvoltage across its voltage sense terminal 553 and its return terminal551, which may reduce an amount of current drain from battery 500. Forexample, in low power mode, current consumption from the battery may bereduced to about 0.3 microamps in the case of a Seiko S8211C batteryprotection IC 501. This reduced current consumption may represent about10% of the current required when the battery protection IC 501 isoperating in normal mode, for example. Additionally and as describedabove, the battery protection IC 501 controls switch 556 to open whilein low power mode. While operating in low power mode, the batteryprotection IC 501 monitors its “VM” pin 561, which as described above iscoupled via current limiting resistor 560 to the return terminal 506 ofthe battery pack 245, and when a sufficiently high voltage is appliedacross the voltage output terminal 504 and the return terminal 506 ofthe battery pack 245, the battery protection IC 501 returns to normalmode and controls switch 556 to close. In this fashion, battery 500 maybe recharged by the charge voltage applied at terminal pins 504 and 506.

The techniques discussed herein involve presenting, across the voltagesense terminal 553 and return terminal 551 of the battery protection IC501, a voltage lower than the predetermined low voltage threshold valueso that the battery protection IC 501 perceives an under-voltagecondition and ceases to monitor the voltage of battery 500. By doing so,the energy supply of the battery 500 may be preserved in an efficientmanner and over-discharge of the battery 500 may be prevented, which mayprolong the useful life of the battery 500. This may be done, forexample, even when a charge potential of the battery 500 (that is, theactual battery voltage) is greater than the predetermined low voltagethreshold value.

For example, in some embodiments the battery 500 may be a 3.8 voltbattery (when fully charged). As described above, the predetermined thelow voltage threshold value for the battery protection IC 501 may beabout 2.8 volts. As a first example, it may be desirable to cause thebattery protection IC 501 to place the battery pack 245 in low powermode at the time the battery pack 245 is manufactured, or when theinfusion pump system 10 is manufactured. In this example, even with afully-charged or nearly fully-charged battery 500, the battery pack 245may be caused to enter a low power mode using the techniques discussedherein, by causing a voltage of less than the low voltage thresholdvalue (2.8 volts in this example) to be presented across the voltagesense terminal 553 and return terminal 551 of the battery protection IC501. This may preserve the charge of the rechargeable battery duringshipping and storage of the infusion pump system 10, so that the unitmay be operational on receipt without first having to charge therechargeable battery 245. As will be described further below, processor522 may initiate the process by setting an output battery disable signal577 low. When a new pump assembly 100′ is attached to the controllerdevice 200 and a charging voltage (e.g., 3.8 volts in some embodiments)is applied across the voltage output terminal 504 and return terminal506 of the battery pack 245, the battery protection IC 501 may bring thebattery pack 245 out of the low power mode.

As a second example, it may similarly be desirable to minimize currentdrain of the rechargeable battery 245 at times after the infusion pumpsystem has been put into service, such as when the pump assembly 100(including charger battery 345) is disconnected from the controllerdevice 200, especially if the controller device remains disconnectedfrom a new pump assembly and charger battery for an extended period oftime, such as one or more days. In this example, the processor 522 mayuse the techniques disclosed herein to cause the battery protection IC501 to place the battery pack 245 in a low power mode when the batteryvoltage reaches a second voltage threshold value, where the secondvoltage threshold value is higher than the predetermined low voltagethreshold value of the battery protection IC 501. For example, when thebattery voltage reaches a second voltage threshold value of about 3.1volts, the processor 522 may set a battery disable output 577 low, whichmay cause the battery protection IC 501 to place the battery pack 245 inthe low power mode, as will be described in more detail below. This maypreserve the charge of the rechargeable battery until a new pumpassembly 100′ is attached to the controller device 200 and therechargeable battery is recharged.

Referring again to FIG. 9, a switch 562, which may be an analog switchin some implementations, operates to couple pins “A” and “B” together(switch closed) while a logic low input is received on an input pin(“IN”) of the switch. At all other times, the switch 562 is open, sothat pins A and B of the switch are disconnected. Pin A of the switch562 is coupled to the return terminal 506 of the battery pack 245, andto the ground reference 575 of battery 500 when switches 556 and 558 areclosed, such as when battery protection IC 501 activates switches 556and 558 (e.g., in normal mode). Pin B of the switch 562 is coupled tothe third terminal 508 of the battery pack 245, and to one terminal of asecond resistor 554. The other terminal of the second resistor 554 iscoupled to the voltage sense terminal 553 of the battery protection IC501.

In operation, when switch 562 receives a logic low input at its “IN”terminal, switch 562 internally switches to couple pins A and Btogether, thereby providing a low-resistance connection between thethird terminal 508 of the battery pack 245 and the return terminal 506of the battery pack 245. A battery disable signal 577 may be received bythe switch 562 at the IN terminal of the switch 562. In someimplementations, the processor 522 controls the battery disable signal577, which is received by the switch 562. The battery disable signal 577may be pulled high by a pull-up resistor (not shown) so that when theprocessor 522 is not driving the signal 577 low the switch 562 sees alogic high input and remains open (i.e., pins A and B not internallyconnected within the switch 562).

Still referring to FIG. 9, when switch 562 closes (e.g., as commanded byprocessor 522) and creates a low-resistance connection between the thirdterminal 508 of the battery pack 245 and the return terminal 506 of thebattery pack 245, the first resistor 550 and the second resistor 554create a resistive divider across the voltage sense terminal 553 of thebattery protection IC 501. Values can be chosen for the first resistor550 and the second resistor 554 so that the resistive divider formed bythe resistors causes a voltage less than the predetermined low voltagethreshold value of the battery protection IC 501 to be presented at thevoltage sense terminal 553 of the battery protection IC 501 for expectedvalues of the battery 500. For example, the first resistor 550 may havea value of 220 ohms, and the second resistor 554 may have a value of 540ohms. In this case, even if battery 500 is fully charged at 3.8 volts, avoltage of 2.7 volts will be presented to the battery protection IC 501when switch 562 closes and current flows through the first resistor 550and the second resistor 554, and the battery protection IC 501 willplace the battery pack 245 in low power mode because the sensed voltage(2.7 volts) is lower than the predetermined low voltage threshold value(2.8 volts).

Referring now to FIG. 10, another schematic diagram of a battery packdevice and circuit for an infusion pump controller is shown. The batterypack device may correspond to the rechargeable battery 245, according tosome implementations. FIG. 10 differs from FIG. 9 in three respects.First, switch 564 is a MOSFET, in contrast to the analog switch 562 ofFIG. 9, but operates in similar fashion, normally remaining open butbeing activated (closed) when the battery disable signal 577 goes low.When the switch 564 closes, a low-resistance connection is providedbetween the third terminal 508 of the battery pack 245 and the returnterminal 506 of the batter pack 245, and a low power mode is entered asdescribed above. Second, safety IC 569 is shown generically with asingle output terminal “O” 571, where the safety IC 569 may activate theoutput terminal 571 when either an under-voltage or over-voltagecondition is sensed. Alternatively, output terminal 571 may correspondto “DO” terminal 557 (FIG. 9) in some implementations. Third, a singleswitch 570 replaces switches 556 and 558 of FIG. 9.

It should be understood that, in some embodiments, the battery packdevice 245 can be triggered to shift into or out of the low powerwithout the use of a switch 562 or 564. For example, as an alternativeto employing the switch 262 or 264 between the processor and the batterypack device, a pin of the processor 522 can be coupled directly to thethird terminal 508 of the battery pack 245, thereby omitting the switch562 (FIG. 9) or 564 (FIG. 10). In such circumstances, an output pin ofprocessor 522 provides the battery disable signal 577 directly to thethird terminal 508 of the battery pack 245, without using devices 562 or564 as buffers. This embodiment may be used, for example, for aprocessor housed in the controller device 200 having an I/O pin rated towithstand a full-battery voltage (e.g., about 3.8V in someimplementations) and rated to sink a current (e.g., about 5 mA in someimplementations) that flows through the resistive divider formed by thefirst resistor 550 and the second resistor 554 when a (logic low)battery disable signal 577 is applied by the processor 522. Accordingly,the processor included in the controller device 200 can be coupleddirectly to the third terminal 508 of the battery pack device in amanner that eliminates the need for the switch 562 (FIG. 9) or 564 (FIG.10).

A number of embodiments have been described. Nevertheless, it will beunderstood that various modifications may be made without departing fromthe spirit and scope of this disclosure. For example, other batterychemistries are also contemplated, particularly those where it isdesirable to prevent excessive charging or discharging across a singlecell of the battery, or across multiple cells of the battery. Also, itis contemplated that an existing signal terminal of a battery pack maybe employed through use of a high-pass filter to separate the batterydisable signal from lower frequency signals normally intended for theterminal, or by use of diode logic to separate positive-going fromnegative-going signals. Accordingly, other embodiments are within thescope of the following claims.

What is claimed is:
 1. A portable infusion pump system, comprising: a pump device including: a pump housing that defines a space to receive a medicine, and a drive system to dispense the medicine from the pump device when the medicine is received in the space of the pump housing; and a controller device electrically connectable to the pump device so as to control dispensation of the medicine from the pump device, the controller device comprising: a battery pack including a voltage output terminal, a return terminal, a third terminal, and at least one rechargeable battery cell that is coupled to the voltage output terminal so as to provide electrical energy to at least one of a component of the controller device and the drive system of the pump device; a monitor circuit that is configured to sense a voltage of the at least one rechargeable battery cell; a first resistor coupled between the at least one rechargeable battery cell and a voltage sense terminal of the monitor circuit; a second resistor coupled between the voltage sense terminal of the monitor circuit and the third terminal of the battery pack; wherein, in response to a user-initiated detachment of the pump device from the controller device, the monitor circuit is configured to cause the battery pack to act according to a low power mode independent of the voltage of the at least one rechargeable battery cell; wherein, in response to the user-initiated detachment of the pump device from the controller device, a low-resistance connection is provided between the third terminal of the battery pack and the return terminal of the battery pack.
 2. The system of claim 1, further comprising a first switch coupled to a return terminal of the monitor circuit and to the return terminal of the battery pack, and controlled by the monitor circuit, wherein the monitor circuit causes the first switch to open when the monitor circuit causes the battery pack to act according to the low power mode, thereby breaking an electrical connection between the return terminal of the monitor circuit and the return terminal of the battery pack.
 3. The system of claim 1, wherein in response to a charging voltage being applied across the voltage output terminal of the battery pack and the return terminal of the battery pack, the monitor circuit is configured to cause the battery pack to act according to a normal mode in which a greater level of electrical current is drawn from the at least one rechargeable battery cell.
 4. The system of claim 3, wherein the pump device further comprises a non-rechargeable battery, and wherein the charging voltage is derived from the non-rechargeable battery and applied across the voltage output terminal and the return terminal of the battery pack when the pump device and the controller device are removable attached to form an electrical connection.
 5. The system of claim 1, wherein the controller device further comprises a processor and a second switch, the second switch coupled between the third terminal of the battery pack and the return terminal of the battery pack, and wherein the processor causes the second switch to close and provide the low-resistance connection between the third terminal of the battery pack and the return terminal of the battery pack.
 6. The system of claim 5, wherein the second switch comprises a MOSFET.
 7. The system of claim 1, wherein the low-resistance connection is provided between the third terminal of the battery pack and the return terminal of the battery pack without an external voltage source applied to any of the voltage output terminal, return terminal, or third terminal of the battery pack.
 8. The system of claim 1, wherein, at a time when the low-resistance connection is provided between the third terminal of the battery pack and the return terminal of the battery pack, a potential of the at least one rechargeable battery cell is greater than a predetermined low voltage threshold value of the monitor circuit.
 9. The system of claim 1, wherein the first resistor and the second resistor comprise a resistive divider across the voltage sense terminal of the monitor circuit when the low-resistance connection is provided between the third terminal of the battery pack and the return terminal of the battery pack.
 10. A method of controlling a portable infusion pump system, comprising: connecting a controller device to a pump device so as to send a control signal from the controller device to the pump device for controlling dispensation of medicine from the pump device, the controller device comprising: a battery pack including a voltage output terminal, a return terminal, a third terminal, and at least one rechargeable battery cell that is coupled to the voltage output terminal and that is configured to provide electrical energy to at least one of a user interface component of the controller device and a drive system of the pump device; a monitor circuit that is configured to sense a voltage of the at least one rechargeable battery cell; a first resistor coupled between the at least one rechargeable battery cell and a voltage sense terminal of the monitor circuit; a second resistor coupled between the voltage sense terminal of the monitor circuit and the third terminal of the battery pack; and providing a low-resistance connection between the third terminal of the battery pack and the return terminal of the battery pack to cause the battery pack to act according to a low power mode independent of the voltage of the at least one rechargeable battery cell; wherein the low-resistance connection between the third terminal of the battery pack and the return terminal of the battery pack is provided in response to a user-initiated detachment of the pump device from the controller device.
 11. The method of claim 10, further comprising applying a charging voltage across the voltage output terminal of the battery pack and the return terminal of the battery pack to cause the battery pack to act according to a normal mode in which a greater level of electrical current is drawn from the at least one rechargeable battery cell.
 12. The method of claim 11, wherein the pump device further comprises a non-rechargeable battery, and wherein the charging voltage is derived from the non-rechargeable battery and applied across the voltage output terminal and the return terminal of the battery pack when the pump device and the controller device are removably attached to form an electrical connection.
 13. The method of claim 10, wherein the controller device further comprises a first switch coupled to a return terminal of a monitor circuit and to the return terminal of the battery pack, and controlled by the monitor circuit, and wherein the monitor circuit causes the first switch to open when the monitor circuit puts the battery pack in the low power mode, thereby breaking an electrical connection between the return terminal of the monitor circuit and the return terminal of the battery pack.
 14. The method of claim 10, wherein the controller device further comprises a processor and a second switch, the second switch coupled between the third terminal of the battery pack and the return terminal of the battery pack, and wherein the processor causes the second switch to close and provide the low-resistance connection between the third terminal of the battery pack and the return terminal of the battery pack.
 15. The method of claim 14, wherein the second switch comprises a MOSFET.
 16. The method of claim 10, wherein providing the low-resistance connection between the third terminal of the battery pack and the return terminal of the battery pack is implemented without applying an external voltage source to any of the voltage output terminal, return terminal, or third terminal of the battery pack.
 17. The method of claim 10, wherein, at a time when the low-resistance connection is provided between the third terminal of the battery pack and the return terminal of the battery pack, a potential of the at least one rechargeable battery cell is greater than a predefined low voltage threshold value.
 18. The method of claim 10, wherein the first resistor and the second resistor comprise a resistive divider across the voltage sense terminal when the low-resistance connection is provided between the third terminal of the battery pack and the return terminal of the battery pack. 